On reducing aliasing in accumulator-based compaction

The utilization of accumulators for time compaction of the responses in built-in self test environments has been studied by various researchers. One of the well-known problems of time compactors is aliasing, i.e. the event that a series of responses containing errors result in a signature equal to that of an error-free response sequence. In this paper we propose a scheme to reduce aliasing in accumulator based compaction environments. With the proposed scheme, the aliasing probability tends to zero, as the number of the patterns of the test set increases.